Making use of an organic electroluminescence element (hereinafter, referred to as an organic EL element) as a light emitting device in various display apparatus is drawing attention thanks to its advantages such as having a high visibility due to light emission by the device itself and an excellent impact resistance due to being a solid-state device. There is also a feature that the organic EL element can be made thin because it is a surface light source. The structure of an organic EL element is based on lamination of an anode, a light emitting layer and a cathode, and a structure in which a transparent anode is formed on a substrate which uses a glass plate or the like is usually adopted. In this case, emitted light is taken out toward the substrate side.
An organic EL element which takes out emitted light from the cathode side is also known. For example, an organic EL element of patent document 2 includes an anode, an organic layer, a barrier property conductive layer having optical transparency and a cathode having optical transparency, which is provided on a substrate in order.
There has been also devised an organic EL element in which the two electrodes are formed of transparent electrodes, and light emission is made toward the both sides. For example, in an organic EL element of patent document 1, a first electrode of optical transparency is provided on a substrate, and an organic layer having at least a light emitting layer is provided on the first electrode. Further, a second electrode of optical transparency is provided on the organic layer, and at least the second electrode is formed of indium oxide.
An organic EL element is expected to be used for a display apparatus because it is of a self-luminosity and is a surface light source. When it is used for a display apparatus, there are several methods for full colorization such as: a method in which organic EL light emitting elements that emit light of three colors of red (R) green (G) and blue (B) are arranged on a substrate for every one pixel (so-called a three-color coloring method); a color conversion method by applying wavelength distribution conversion to emitted light from the backlight (hereinafter, referred to as CCM method); and a color filtering method to radiate emitted light from backlight through a color filter (patent document 3). In patent document 3, there is described a passive-matrix-drive top emission type EL element using CCM method.
Also, in patent document 4, there is described a surface-emitting light source which improves luminance by improving light extraction efficiency. In a surface-emitting light source according to patent document 4, there is formed on a surface of a transparent substrate a light emitting element constituted of a laminated body of: a transparent electrode; a light emitting layer including an organic EL layer; and a reflection electrode. The light emitting element has a prismatic structure face of a multiple-plane structure on a surface of a transparent substrate. As a result, a bend section is made to be provided in a light emitting layer, and total reflection light within the light emitting layer is taken out from the bend section. By making a light emitting element be of a multiple plane structure, practical improvement of luminance by increase of a luminous area is achieved.